The National Agenda for Action: The National Public Health Initiative on Diabetes and Women's Health has developed an action plan to "mobilize the nation to address diabetes as a growing health concern." It calls for expanding community based education programs, promoting risk assessment, supporting quality care and self-management for diabetes and its complications and encouraging research into the factors that influence diabetes and women's health. This proposal is timely in addressing this issue as related to gestational diabetes mellitus (GDM) and maternal and fetal health. GDM occurs in approximately 5% of pregnant women with onset during pregnancy, and subsiding after parturition. Importantly nearly 5o% of women with GDM will eventually develop type 2 diabetes mellitus within 3-5 years post-partum. Moreover, acute and chronic neonatal morbidity and mortality have been described in neonates delivered by women with GDM. Substantial evidence is available documenting that the severity of periodontal disease is increased in patients with type 2 diabetes but no data are available on the effects of GDM on periodontal health. In addition, substantial data is accruing to support earlier observations that the infection and inflammation associated with periodontal disease may have a negative impact on the period of gestation and on fetal growth leading to the birth of preterm, low birth weight infants. Our GENERAL HYPOTHESIS is that women with GDM are at higher risk for developing more severe periodontal disease than women without GDM and that the combination of GDM and periodontal disease will be associated with an increased negative impact on maternal and fetal health. The following Specific Aims are designed to address this question. Specific Aim 1: to characterize the prevalence, extent and severity of periodontitis and associations between periodontitis and adverse maternal and fetal outcomes in women who develop GDM compared to women who don't develop GDM. Specific Aim 2: will characterize the subgingival microbial ecology in women with GDM and periodontal disease and determine if specific microbial characteristics are associated with adverse pregnancy and fetal outcomes. Specific Aim 3: will determine if patients with GDM and periodontitis have elevated levels of circulating inflammatory mediators compared to women with GDM and no periodontitis and the non-GDM controls. The innovative aspects of the project include conducting seminal studies to document a link between periodontitis, GDM and negative maternal and/or fetal outeomes. We will use prospective clinical studies correlated with basic science laboratory evaluations to provide insight into the pathogenic mechanisms contributing to negative maternal and fetal outcomes associated with inflammatory, periodontal disease and GDM. The results obtained from this: study will provide the groundwork for future clinical trials designed to evaluate the impact of non-surgical, interventional periodontal therapy on the control of GDM and its related negative outcomes.